Resin composition for aqueous paints

ABSTRACT

A resin composition for an aqueous coating composition contains as a main component a cationic resin (U) having a primary hydroxyl group, obtained by reacting (A) a phenol-novolak epoxy resin, (B) a primary or secondary amine compound having a primary hydroxyl group, and (c) a phenol compound having at lest one phenolic hydroxyl group per molecule. The composition has improved water dispersibility, bath stability and pigment dispersibility, and is useful as a cationic electrodeposition coating composition.

This invention relates to a resin composition for aqueous coatingcompositions and more particularly to a resin composition for aqueouscoating compositions which is useful as a resin composition for cationicelectrodeposition coating compositions and which is excellent indispersibility in water, bath stability and dispersibility of pigmentstherein.

As a base resin for cationic electrodeposition coating compositions,there have generally been used amine-added epoxy resins obtained byreaction between a diepoxide having a high molecular weight (numberaverage molecular weight of about 1,000 or more) and a secondary amine(for example, diethanolamine, methylethanoiamine, diethylamine, etc.).These resins can be hardened by crosslinking reaction with a blockedpolyisocyanate compound or the like, and therefore their coating filmsare excellent in corrosion resistance. However, the aforementionedamine-added epoxy resins are made insufficiently water-dispersible bypartial neutralization with acids because they contain tertiary aminegroups as a cationic group. On the other hand, full neutralizationthereof results in lowering of the pH of a resulting electrodepositioncoating bath inducing a problem of insufficient corrosion resistance ofthe composition.

It is widely known that crosslinking agents such as blockedpolyisocyanate compounds rapidly react with primary hydroxyl groups of abase resin to crosslink and harden it. Also, it is known that aneffective measure to introduce primary hydroxyl groups in a base resinfor a cationic electrodeposition coating composition containing aglycidyl ether of bisphenol A type as a basic skeleton is to use asecondary alkanolamine as a secondary amine. However, use of suchsecondary amines decreases water dispersibility as described above.

Also, it has been tried to use a reaction product between a polyepoxidehaving three or more epoxy groups per molecule (epoxy equivalent: 100 to1,000) and a polyphenol (for example, alkylene diphenol) as a base resinfor a cationic electrodeposition coating composition. This trial hasrevealed impractical results since there occurs an increase in theviscosity of the reaction mixture or gelation during the reactionbetween the polyepoxide and the polyphenol. In addition, amine-addedproduct of the polyepoxide is undesirable because it gives rise to alocal increase in the base concentration so that the corrosionresistance of the resulting resin deteriorates.

Further, a base resin for a cationic electrodeposition coatingcomposition is known which is obtained by reacting a specifiedpolyepoxide with a primary or secondary amine containing a primaryhydroxyl group. Although this base resin has excellent waterdispersibility upon partial neutralization with an acid, the increasedpolyepoxide concentration intended to increase water dispersibilitynecessarily leads to a decrease in the concentration of benzene nucleusthat controls the corrosion resistance of the resin since thepolyepoxide has an alicyclic nucleus.

Therefore, there has been a strong desire to develop a cationic baseresin for use in electrodeposition to which primary hydroxyl groups canbe incorporated with a secondary alkanolamine and which has excellentwater dispersibility during partial neutralization and excellentcorrosion resistance after coating.

An object of this invention is to provide a resin composition for anaqueous coating composition which is useful as a base resin for acationic electrodeposition coating composition, which is free fromincrease in viscosity and occurrence of gelation during its synthesisreaction, which has excellent water dispersibility even in the cases ofpartial neutralization, and which has excellent corrosion resistanceafter coating as well as a cationic electrodeposition coatingcomposition using such a resin composition.

According to one aspect of this invention, there is provided a resincomposition for an aqueous coating composition, comprising as a maincomponent a cationic resin (U) having a primary hydroxyl group obtainedby reacting:

(A) a phenol-novolak type epoxy resin represented by the followinggeneral formula (I) ##STR1## wherein R₁ and R₂, which are the same ordifferent, independently represent a hydrogen atom, an alkyl grouphaving 1 to 8 carbon atoms, an aryl group, an aralkyl group or a halogenatom;

R₃ represents a hydrogen atom, an alkyl group having 1 to 10 carbonatoms, an aryl group, an aralkyl group, an allyl group or a halogenatom;

R₄ and R₆, which are the same or different, independently represent ahydrogen atom, an alkyl group having 1 to 4 carbon atoms or aglycidyloxyphenyl group;

R₅ represents a hydrogen atom, an alkyl group having 1 to 10 carbonatoms, an aryl group, an aralkyl group, an allyl group or a halogenatom; and

n is an integer of 1 to 38,

(B) a primary or secondary amine compound having a primary hydroxylgroup; and

(C) a phenol compound having at least one phenolic hydroxyl group permolecule.

According to another aspect of this invention, there is provided acationic electrodeposition coating composition (V) comprising as a maincomponent a mixture of the aforementioned cationic resin (U) having aprimary hydroxyl group, and a hardening agent (H) selected preferablyfrom (H-1) a blocked polyisocyanate compound, (H-2) a polyepoxidecompound, and (H-3) a compound having two or more unsaturated groups permolecule.

According to a further aspect of this invention, there is provided:

A resin composition (W) for a self-hardening coating compositionobtained by partially reacting the cationic resin (U) having a primaryhydroxyl group with the hardening agent (H);

A cationic electrodeposition coating composition (X) comprising as amain component the resin composition (W) for a self-hardening coatingcomposition;

A pigment-dispersed paste (Y) comprising the cationic resin (U) having aprimary hydroxyl group or the resin composition (W) for a self-hardeningcoating composition, and a pigment (G); and

Articles coated with the cationic electrodeposition coating composition(V) or the cationic electrodeposition coating composition (X).

Hereinafter, further explanation will be made on the resin composition,cationic electrodeposition coating composition and pigment paste of thisinvention.

Component (A) Phenol-novolak type epoxy resin represented by thefollowing general formula (I) ##STR2##

R₁ and R₂, which are the same or different, independently represent ahydrogen atom, an alkyl group having 1 to 8 carbon atoms, an aryl group,an aralkyl group or a halogen atom;

R₃ represents a hydrogen atom, an alkyl group having 1 to 10 carbonatoms, an aryl group, an aralkyl group, an allyl group or a halogenatom;

R₄ and R₆, which are the same or different, independently represent ahydrogen atom, an alkyl group having 1 to 4 carbon atoms or aglycidyloxyphenyl group; and

R₅ represents a hydrogen atom, an alkyl group having 1 to 10 carbonatoms, an aryl group, an aralkyl group, an allyl group or a halogenatom; and

n is an integer of 1 to 38.

In the above general formula (I), "alkyl group" is straight chain orbranched chain, and includes, for example, methyl, ethyl, propyl,isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isoamyl,hexyl, heptyl, octyl, 2-ethylhexyl, nonyl, decyl, etc. groups. "Arylgroup" may be either monocyclic or polycyclic, and includes, forexample, phenyl, naphthyl, etc. groups. In particular, a phenyl group ispreferred. "Aralkyl group" is an aryl-substituted alkyl group of whichthe aryl and alkyl moieties have the aforementioned meanings,respectively. Examples thereof include, for example, benzyl, phenethyl,etc. groups, with a benzyl group being preferred.

"Halogen atom" includes a fluorine atom, a chlorine atom, a bromine atomand an iodine atom.

"Organic group having a glycidyloxyphenyl group" which can berepresented by R₄ and/or R₆ is an organic group having a grouprepresented by formula ##STR3## wherein W is a hydrogen atom or an alkylgroup having 1 to 10 carbon atoms. Preferred examples of the organicgroup include, for example, glycidyloxyphenyl, glycidyloxyphenylmethyl,glycidyloxyphenylethyl, glycidyloxyphenylpropyl, glycidyloxyphenylbutyl,glycidyloxyphenylpentyl, glycidyloxyphenylhexyl, glycidyloxyphenyloctyl,glycidyloxyphenylnonyl, etc. groups.

In the general formula (I), R₁ and R₂ are preferably a hydrogen atom, amethyl group, a chlorine atom, or a bromine atom, with a hydrogen atom,a methyl group and a bromine atom being particularly preferred. R₃ andR₅ are preferably a methyl group, a tert-butyl group, a nonyl group, aphenyl group, a chlorine atom or a bromine atom, with a methyl group, atert-butyl group, a phenyl group and a bromine atom being particularlypreferred. Further, R₄ and R₆ are preferably a hydrogen atom, and n ispreferably 1 to 25, and more preferably 1 to 8.

It is preferred that the epoxy resin (A) has a number average molecularweight within the range of generally about 400 to 8,000, particularly500 to 3,000 and more particularly 600 to 2,000, as measured by a vaporpressure-osomotic pressure method. From this number average molecularweight one can calculate a number average repeating unit number (n+2).Also, it is preferred that the epoxy resin (A) has in average generally3.5 to 10, particularly 3.5 to 8, and more particularly 4 to 7, glycidylgroups per molecule, and that the epoxy resin (A) has an epoxyequivalent within the range of about 180 to about 2,000, particularly180 to 1,000, and more particularly 180 to 600.

The epoxy resin (A) can be prepared, for example, by reactingepihalohydrin (A-5) with a phenol-novolak type resin (A-4) which isobtained by polycondensation reaction between a bifunctional phenylcompound (A-1) represented by the following general formula (III)##STR4## wherein R₁, R₂ and R₃ have the same meanings as defined above,and an aldehyde compound (A-2) represented by the following generalformula (IV)

    R.sub.4 --CHO                                              (IV)

wherein R₄ has the same meaning as defined above, and/or a ketonecompound (A-3) represented by the following general formula (V)

    R.sub.4 --CO--R.sub.6                                      (V)

wherein R₄ and R₆ have the same meanings as defined above, to introducea glycidyl ether group in the phenolnovolak type resin (A-4).

During or after the reaction for obtaining the aforementionedphenol-novolak resin (A-4), a monofunctional phenol compound (A-6)represented by the following general formula (VI) ##STR5## wherein R₇represents a alkyl group having 1 to 10 carbon atoms, an aryl group, anaralkyl group, an allyl group or a halogen atom; and

R₁ and R₂ have the same meanings as defined above,

may be used in combination as a terminal blocking agent, as necessary.

Specific examples of the group represented by R₇ in the formula (VI)above include a methyl group, an ethyl group, a propyl group, an n-butylgroup, a tertbutyl group, a pentyl group, a hexyl group, a nonyl group,an ethylene group, a propylene group, a phenyl group, a benzyl group, achlorine atom, a bromine atom, and an iodine atom, with a methyl group,a tert-butyl group, a nonyl group, a phenyl group, a chlorine atom, anda bromine atom being particularly preferred.

The term "bifunctional" as used for the phenol compound as component(A-1) above means that in general formula (III), two hydrogen atoms arebonded to directly to the benzene nucleus at the ortho and/orpara-position with respect to the hydroxyl group. The hydrogen atomswill react with carbonyl group (C═O) in the components (A-2) and (A-3)above by condensation reaction with dehydration to form a phenol-novolakresin (A-4).

The term "monofunctional" as used for the phenol compound as component(A-6) means that in the general formula (IV), one hydrogen atom isbonded to the benzene ring at the ortho- or para-position with respectto the hydroxyl group. The hydrogen atom will react with carbonyl group(C═O) in the component (A-2) or (A-3) above by condensation reactionwith dehydration to form terminals thereof.

As the bifunctional compound (A-1) represented by the formula (III)above, there can be cited, for example, phenol, p-propenylphenol,o-benzylphenol, 6-n-amyl-n-cresol, o-cresol, p-cresol, o-ethylphenol,o-phenylphenol, p-phenylphenol, P-tert-pentylphenol, p-tert-butylphenol,o-chlorophenol, p-chlorophenol, 4-chloro-3,5-xylenol, o-allylphenol,nonylphenol, o-bromophenol, p-cumylphenol, etc.

As the aldehyde compound (A-2) represented by the formula (IV) above,there can be cited, for example, acetaldehyde, formaldehyde, etc. Also,m- (or p-) hydroxybenzaldehyde may be used as the aldehyde compound(A-2), and after the reaction with the component (A-1), thehydroxybenzaldehyde may be converted to glycidyl ether with theepihalohydrin (A-5). The benzene nucleus of the hydroxybenzaldehyde maybe substituted with am alkyl group having 1 to 10 carbon atoms.

As the ketone compound (A-3) represented by the formula (V), there canbe cited, for example, acetone, methyl ethyl ketone, methyl isobutylketones, etc. Further, use of 2-acetylphenyl-2-hydroxyphenylpropanemakes it possible to introduce a glycidyloxyphenyl group in the resinrepresented by the formula (I) above

This makes at least a portion of ##STR6##

Further, as the epihalohydrin (A-5), there can be cited, for example,epichlorohydrin, epibromohydrin, etc.

The phenol-novolak resin (A-4) can be obtained by polycondensing the(A-1) component above with the (A-2) and/or (A-3) component above. Thepolycondensation reaction can be performed similarly to an ordinaryproduction method for phenol-novolak resin which is known by itself.More specifically, the reaction may be performed by a batch method, orby the continuous method as described, for example, in Japanese PatentApplication Laid-Open NO. 130498/1976. For example, the (A-4) componentcan be obtained by blending each component in proportions such that therepeating unit number (n) in the formula (I) above is within the rangeof 1 to 38, and the number average molecular weight and epoxy equivalentare within the aforementioned ranges, followed by reaction. In thisreaction, there may be used a catalyst such an inorganic acids, e.g.,hydrochloric acid, phosphoric acid, sulfuric acid, etc.; organic acids,e.g., p-toluenesulfonic acid, oxalic acid, etc.; metal salts, e.g., zincacetate, etc.

In the production of the (A-4) component, the monofunctional phenolcompound (A-6) represented by the formula (VI) above may be reacted as aterminal blocking agent during or after polycondensation reaction of the(A-1) component with the (A-2) component and/or (A-3) component asnecessary.

Specific examples of the monofunctional phenol compound (A-6)represented by the formula (VI) above include, for example,2-tert-butyl-4-methylphenol, 2,4-xylenol, 2,6-xyloneol,2,4-dichlorophenol, 2,4-dibromophenol, dichloroxylenol, dibromoxylenol,2,4,5-trichlorophenol, 6-phenyl-2-chlorophenol, etc.

The polycondensation of the (A-6) component with the (A-1) component,(A-2) component and/or (A-3) component above can be performed in thesame manner as described above. Novolak-phenol resin obtained using the(A-6) component in combination is also included in the category of the(A-4) component.

The (A) component can be obtained by reacting the (A-5) component withphenolic hydroxyl groups in the (A-4) component to convert them intoglycidyl ether. More specifically, for example, the (A-4) component isdissolved in the (A-5) component, and an aqueous solution of an alkalimetal hydroxide is continuously added to the resulting solution,followed by distilling off water and unreacted (A-5) component in thereaction mixture. From the the distillate can be removed (A-5)component, which can be reused. This reaction can be performedpreferably in the presence of an ether type solvent such as dioxane,diethoxyethane, etc.

The component (A) may be one which has been produced as described aboveor one which is commercially available. As such a commercially availableproduct, there can be cited, for example, DEN-438 and DEN-439 (tradenames for products by Dow Chemical Japan Co., Ltd.) as polyglycidylether product of phenol-novolak resin; EPICRON N-695 (trade name for aproduct by DAINIPPON INK AND CHEMICALS INDUSTRY CO., LTD.), ESCN-195XHH(trade name for a product by SUMITOMO CHEMICAL CO., LTD.), EOCN-102S,EOCN-1020 and EOCN-104S (trade names for products by NIPPON KAYAKU CO.,LTD.) as polyglycidyl ether products of cresol-novolak resins; BREN-S(trade name for a product by NIPPON KAYAKU CO., LTD.) as polyglycidylether product of bromine-modified phenolnovolak resin; ESMB-260 (tradename for a product by SUMITOMO CHEMICAL CO., LTD.) as polyglycidyl etherproduct of long-chain alkyl-modified phenol-novolak resin; etc.

Component (B) Primary or secondary amine compound having at least oneprimary hydroxyl group per molecule

This component reacts with the component (A) above and serves tointroduce primary hydroxyl group and basic group(s) in the component(A).

Reaction between amino groups in the component (B) and glycidyl groupsrepresented by formula (I) in the component (A) produces cationic resinhaving primary hydroxyl groups and basic groups. The cationic resin issuperior in water dispersibility and throwing power even after partialneutralization or at high pH over the aforementioned conventionalcationic resin produced by reaction between the conventional bisphenol Atype epoxy resin, and does not deteriorate hardenability and corrosionresistance of a coating film formed.

As the component (B), there can be cited the following compounds.

(1) Monoalkanolamines such as monoethanolamine, monopropanolamine,monobutanolamine, etc.

(2) N-Alkylalkanolamines or N,N-dialkanolamines such asN-methylethanolamine, N-ethylethanolamine, N,N-diethanolamine,N,N-di-n-(or iso-)propanolamine, N,N-dibutanolamine, etc.

(3) Addition product of monoalkanolamine and α,β-unsaturated carbonylcompound: for example, addition product of monoethanolamine andN,N-dimethylaminopropylacrylamide, addition product of monoethanolamineand hydroxylethyl (meth)acrylate, addition product of monoethanolamineand hydroxypropyl (meth)acrylate, addition product of monoethanolamineand hydroxybutyl (meth)acrylate, etc.

(4) Hydroxyalkylaminoalkylamine such as hydroxyethylaminoethylamine,

(5) Condensation product between at least one compound selected fromhydroxyethylamine, hydroxyethylhydrazine and hydroxybutylhydrazine and aketone compound, for example, dimethyl ketone, methyl ethyl ketone,methyl isobutyl ketone, dibutyl ketone, dipropyl ketone, etc.

(6) Amine compound having a primary hydroxyl group, a secondary aminogroup and an amido group in one molecule simultaneously, represented bythe following general formula (VII) ##STR7## wherein m is an integer of1 to 6;

R₂₁ is hydrocarbon chain having 4 to 36 carbon atoms which may contain ahydroxyl group and/or a polymerizable unsaturated group.

The amine compound represented by the general formula (VII) can beobtained, for example, by condensation with dehydration betweenN-hydroxyalkylalkylenediamine and a monocarboxylic acid having 5 to 37carbon atoms. As the amine, there can be used preferably diamines havinga primary hydroxyl group, such as hydroxyetheylaminoethylamine,N-hydroxyethylpropylenediamine, N-hydroxyethylbutylenediamine,N-hydroxyethylpentylenediamine, N-hydroxyethylhexylenediamine, etc. Asthe monocarboxylic acid, there can be cited, for example, mixed fattyacids such as coconut oil fatty acid, castor oil fatty acid, rice branoil fatty acid, soy bean fatty acid, tall oil fatty acid, dehydratedcastor oil fatty acid, safflower oil fatty acid, linseed oil fatty acid,and tung oil fatty acid; caprylic acid, capric acid, lauric acid,myristic acid, palmitic acid, stearic acid, oleic acid, ricinolic acid,rinolic acid, rinoleic acid, eleostearic acid, 12-hydroxystearic acid,behenic acid, etc.

The reaction between the aforementioned amine and monocarboxylic acidfor obtaining the amine compound represented by the formula (VII) abovecan be performed usually by mixing the both components in equimolarproportions, removing a predetermined amount of reaction product waterusing an organic solvent such as toluene or methyl isobutyl ketone, andthen removing the remaining organic solvent by a vacuum evaporationmethod or the like to obtain an amine compound. It is preferred that theamine compound thus obtained has an amine (secondary amine) value withinthe range of generally 88 to 350, particularly 120 to 230, and moreparticularly 130 to 200, and a hydroxyl value, preferably primaryhydroxyl value, (KOH mg/g) within the range of generally 44 to 350,particularly 60 to 230, and more particularly 65 to 200.

Among (1) to (6) as the component (B), the amine compounds (2), (3) and(6) above are preferred. In particular, it is preferred to use the aminecompound represented by the formula (VII) (especially hydroxyethylaminefatty acid amide) and diethanolamine in combination in order to improveproperties of the coated surface such as smoothness and corrosionresistance. Preferably, the proportion of the amine compound (especiallyhydroxyethylaminoethyl fatty acid amide) to diethanolamine is 30 to 80%by weight, particularly 40 to 80% by weight, of the former and 70 to 20%by weight, particularly 60 to 20% by weight, of the latter based ontotal weight of the both components.

Component (C) Phenol compound having at least one phenolic hydroxylgroup per molecule

Phenol compound having a phenolic hydroxyl group as the component (C) isdesirably one which has among others at least one, preferably 1 to 4,and more preferably 1 to 2, structural units represented by thefollowing general formula (VIII) ##STR8## wherein R₃₃ and R₃₄, which arethe same or different, independently represent a hydrogen atom, an alkylgroup having 1 to 10 carbon atoms, an aryl group, an aralkyl group, anallyl group or a halogen atom, and the component (C) has a numberaverage molecular weight within the range of usually 94 to 20,000,particularly 150 to 5,000, and more particularly 200 to 3,000.

Specific examples of the component (C) include polyphenol compounds suchas bis(4-hydroxyphenyl)-2,2-propane, 4,4'-dihydroxybenzophenone,bis(4-hydroxyphenyl)-1,1-ethane, bis(4-hydroxyphenyl)-1,1-isobutane,bis(4-hydroxy-tert-butylphenyl)-2,2-propane,bis(2-hydroxynaphthyl)methane, 1,5-dihydroxynaphthalene,bis(2,4-dihydroxyphenyl)methane,1,1,2,2,-tetrakis(4-hydroxyphenyl)ethane, 4,4'-dihydroxydiphenyl ether,4,4'-dihyroxydiphenylsulfone, phenol-novolak, and cresol-novolak;monphenol compounds such as phenol, nonylphenol, α- or β-naphthol,p-tert-octylphenol, and o- or p-phenylphenol.

In this invention, the corrosion resistance of a coating film can befurther increased by the use of compounds component (C) containing afunctional group having a phenolic hydroxyl group, represented by thefollowing general formula (II) ##STR9## wherein R₃₁ and R₃₂, which arethe same or different, independently represent an alkyl group having 1to 4 carbon atoms; and

R₃₃ and R₃₆, which are the same or different, independently represent ahydrogen atom, an alkyl group having 1 to 10 carbon atoms, an arylgroup, an aralkyl group, an allyl group or a halogen atom.

There is no limitation on the number average molecular weight of thecomponent (C) containing the functional group having a phenolic hydroxylgroup represented by the formula (II) above, and is preferably withinthe range of generally 500 to 20,000, particularly 500 to 5,000, andmore particularly 800 to 3,000. It is preferred that the component (C)contains in average 0.3 to 2, particularly 0.5 to 1.5, and moreparticularly 0.8 to 1.2 functional groups having a phenolic hydroxylgroup represented by the formula (II) above per molecule.

In addition, there can be favorably used, as the compound (component(C)) containing the functional group having a phenolic hydroxyl grouprepresented by the formula (II) above, a compound represented by thefollowing general formula (IX) ##STR10## wherein q is 0 or integer of 1to 7; and

R₃₈ represents a residual group of an active hydrogen-containingcompound.

As the active hydrogen-containing compound which is a precursor of R₃₈in the formula (IX) above, there can be cited, for example, amines suchas secondary amines; phenols such as phenylphenol and nonylphenol;organic acids such as fatty acids; thiols; alcohols such as alkylalcohols, cellosolve, butylcellosolve, and carbitol; inorganic acids;and so on. Among them, particularly preferred are secondary amineshaving a primary hydroxyl group such as dialkanolamines; amine compoundsrepresented by the formula (VII) above; phenols such as nonylphenol,phenylphenol, phenol, and hydroquinone monomethyl ether; fatty acidssuch as stearic acids, oleic acid, and soy bean fatty acid; lowerorganic acids such as acetic acid, formic acid, and hydroxyacetic acid;and so on.

A compound the same as that represented by the formula (IX) except thatthe both ends thereof are only one of R₃₈ and --OH instead of R₃₈ and--OH my be present in the component (C) as a mixture. It is preferredthat the compound contains the functional group having a phenolichydroxyl group in an amount of in average 0.5 to 1.5, particularly 0.8to 1.2 per one molecule, and a number average molecular weight withinthe range of 500 to 20,000, particularly 800 to 3,000.

The component (C) containing the functional group having a phenolichydroxyl group can be obtained, for example, by reacting a bisphenoltype glycidyl ether, a bisphenol type diphenol and an activehydrogen-containing compound (for example, N-alkylalkanolamine,dialkanolamine, etc.) in the presence of a catalyst and a solvent asnecessary at a temperature of 30° to 300° C. preferably 70° to 180° C.In this reaction, there may be present as a mixture, polyols such asdimer diol, ethylene glycol, propylene glycol, and butylene glycol;polyether polyols such as polyethylene glycol, polypropylene glycol, andpolybutylene glycol; polyester polyols such polycaprolactone;polycarboxylic acids; polyisocyanates; monoisocyanates; oxides ofunsaturated compounds such as ethylene oxide, propylene oxide, butyleneoxide, and styrene oxide; glycidyl ethers hydroxyl group-containingcompounds such as allyl glycidyl ether, polypropylene glycol diglycidylether, 2-ethylhexyl glycidyl ether, methyl glycidyl ether, butylglycidyl ether, and phenyl glycidyl ether; glycidyl esters or organicacids such as fatty acids; alicyclic oxirane-containing compounds; andso on. Further, d-4-caprolactone, acrylic monomer, etc. may be graftpolymerized thereon.

Cationic Resin (U)

The cationic resin (U) having a primary hydroxyl group according to thisinvention can be obtained by reacting the components (A), (B) and (C)above. This reaction may be performed by reacting the component (A) withthe components (B) and (C). For example, the components (A), (B) and (C)are reacted simultaneously; first the component (A) is reacted with thecomponent (B), and then the component (C) is reacted; first thecomponent (A) is reacted with the component (C), and then the component(B) is reacted; and so on, and thus the cationic resin (U) is obtained.

The reaction between the components (A) and (B) is a reaction betweenthe glycidyl group in the component (A) and the primary and/or secondaryamino group in the component (B), which reaction produces a secondaryand/or tertiary amino group, respectively. Also, the reaction betweenthe components (A) and (C) is a reaction between the glycidyl group inthe component (A) and the phenolic hydroxyl group in the component (C),which reaction produces an ether bond. The cationic resin (U) thusobtained contains no or substantially no remaining glycidyl group (itcontains substantially no glycidyl group) since as a rule the glycidylgroup contained in the component (A) is consumed in the aforementionedreaction.

Proportions of the components are not critical and may be selectedfreely depending on the purposes. For example, it is preferred that thereaction proceeds such that total mole number of the amino group in thecomponent (B) and the phenolic hydroxyl group in the component (C) is0.75 to 1.5 moles, particularly 0.8 to 1.2 moles for 1 mole of glycidylgroups in component (A). If the total mole number is less than 0.75mole, the viscosity of the product could sometimes become high while useof the total mole number above 1.5 moles could result in increasedamount of remaining unreacted amino group which gives adverse influenceon electrodeposition characteristics. Further, the amount of thecomponent (A) to be used is suitably 0.5 to 75% by weight, particularly5 to 50% by weight, and more particularly 7 to 20% by weight, based ontotal weight of the components (A), (B) and (C). If it is less than 0.5%by weight, the resulting resin tends to have insufficient waterdispersibility, and on the contrary, if it exceeds 75% by weight, theamine value increases to high enough a level to deteriorate corrosionresistance of the resulting coated film. It is desirable to use thecomponent (B) in amounts such that the hydroxyl equivalent of theresulting cationic resin (U) is within the range of 250 to 2,000,preferably 300 to 1,000, and more preferably 300 to 700, and the aminevalue is within the range of 15 to 200, preferably 20 to 150, and morepreferably 30 to 100. If the hydroxyl equivalent is below 250, the aminevalue tends to increase to deteriorate the corrosion resistance of theresulting coated film while if it exceeds 2,000, the hardenability ofthe resin decreases, which causes a fear that the corrosion resistanceof the resulting coated film decreases. On the other hand, it issuitable that the component (C) is used in an amount within the range of0.05 to 1.5 moles, particularly 0.2 to 1.2 moles, and more particularly0.3 to 1.0 mole, per mole of the component (A). If the amount of thecomponent (C) is less than 0.05 moles, the water dispersibility of theresin tend to decrease, while if it exceeds 1.5 moles smoothness of thecoated surface tends to decrease.

Further, it is preferred that the reaction between the components (A),(B) and (C) proceeds at a temperature within the range of usually 50° to300° C. particularly 70° to 200° C. This reaction can be performed inthe presence of an organic solvent such as an alcohol, a ketone or anether.

It is preferred that the cationic resin (U) obtained has a numberaverage molecular weight within the range of generally 1,000 to 20,000,particularly 1,500 to 10,000, and more particularly 1,500 to 4,000.Also, it is preferred that the cationic resin, as described above, has ahydroxyl equivalent within the range of generally 250 to 2,000,particularly 300 to 1,000, and more particularly 300 to 700, and anamine value within the range of generally 15 to 200, particularly 20 to150, and more particularly 30 to 100.

Upon the production of the cationic resin (U), other cationizing agents(D) described below may be used together with the component (B) in orderto adjust the hydroxyl equivalent and amine value within theaforementioned ranges, respectively. The component (D) may be used at aninitial stage or in the midway of the aforementioned reaction, or afterthe reaction.

As the other cationizing agent (D), there can be cited, for example,primary amines represented by monoalkylamines such as methylamine,ethylamine, and n- or iso-propylamine; secondary amines represented bydialkylamines such as diethylamine, dipropylamine, and dibutylamine;polyamines represented by alkylene polyamines such as ethylenediamine,diethylenetriamine, ethylaminoethylamine, methylaminopropylamine,dimethylaminoethylamine, and dimethylaminopropylamine; and so on.Further, these may be used together with ammonia, hydrazine,N-hydroxyethylimidazoline compound, etc.

As the other cationizing agent (D), there can also be used aminecompounds which have a secondary hydroxyl group, a secondary amino groupand an amido group simultaneously in one molecule, obtained by replacingthe primary hydroxyl group-containing primary and/or secondary diamineby a secondary hydroxyl group-containing primary and/or secondarydiamine in the preparation of the amine compound (6) as described on thecomponent (B) above.

Further, tertiary amines such as triethylamine, triethanolamine,N,N-dimethylethanolamine, N-methyldiethanolamine,N,N'-diethylethanolamine, and N-ethyldiethanolamine may be used as thecomponent (D). These may also be used in the form of quaternary saltsobtained by protonating with an acid followed by reaction with an epoxygroup.

In addition to the amino compounds, there can be used tertiary sulfoniumsalts obtained by reacting salts of sulfides such as diethyl sulfide,diphenyl sulfide, tetramethylene sulfide and thiodiethanol with boricacid, carbonic acid, organic moncarboxylic acid or the like with anepoxy group.

Further, there can be used, as the cationizing agent, quaternaryphosphonium salts obtained by reacting salts of phosphines such astriethylphosphine, phenyldimethylphosphine, diphenylmethylphosphine, andtriphenylphosphine with the above acid with an epoxy group.

In this invention, while it is necessary to form to cationic resin (U)using the component (B), use of the aforementioned other cationizingagent (D) is not mandatory.

The cationic resin (U) containing a primary hydroxyl group thus obtainedis used preferably as a resin for a cationic electrodeposition coatingcomposition. In particular, the resin (U) is excellent in waterdispersibility and hence it can be blended with an organic or inorganicsubstance having insufficient water dispersibility to improve its waterdispersibility. Therefore, the resin (U) is useful as a waterdispersibility improving agent for a cationic electrodeposition coatingcomposition.

Cationic Electrodeposition Coating Composition (V)

The electrodeposition coating composition (V) of this invention is anaqueous coating composition containing, as a main component, a mixtureof the cationic resin (U) containing a primary hydroxyl group asdescribed above and a hardening agent (H).

As the hardening agent (H), there can be used conventional hardeningagents for cationic electrodeposition coating compositions. Inparticular, those compounds are preferred which are selected, forexample, from a blocked polyisocyanate compound (H-1), a polyepoxidecompound (H-2), and a compound having two or more unsaturated groups permolecule (H-3) as described below.

(H-1) Blocked Polyisocyanate Compound

The compound is a polyisocyanate compound having two or more isocyanategroups which are blocked with an active hydrogen-containing blockingagent such as a hydroxyl group. When heated to temperature above apredetermined temperature, the blocking agent is released to regeneratefree isocyanate groups, which react with the hydroxyl groups of thecationic resin (U) to crosslink and harden it. As the polyisocyanatecompound, there can be used aliphatic, aromatic, and arylaliphaticpolyisocyanate compounds, and any known blocking agents can be used.More specifically, those compounds may be used which are described, forexample, in Japanese Patent Publication No. 6306/1977, and JapanesePatent Application Laid-Open No. 759/1972 which are incorporated hereinby reference. To summarize the contents of the aforementioned JapanesePublications, examples of the polyisocyanate compound include organicdiisocyanates per se, e.g., aliphatic diisocyanates such ashexamethylene diisocyanate and trimethylhexamethylene diisocyanate;alicyclic diisocyanates such as hydrogenated xylylene diisocyanate andisophorone diisocyanate; aromatic diisocyanates such as tolylenediisocyanate and 4,4'-diphenylmethane diisocyanate, or addition productsof the organic diisocyanates with polyhydric alcohols, low molecularweight polyester resins or water, cyclic polymerization products betweenthe organic diisocyanates, or isocyanate biuret products.

Further, the blocking agent is preferably the one which releases uponheated at a temperature of 100° C. or higher in the presence or absenceof a catalyst such as an organometallic compound including tin, lead orthe like or an amino compound. For example, there can be used phenolblocking agents, lactam blocking agents, active methylene blockingagents, alcohol blocking agents, mercaptan blocking agents, acid amidblocking agents, imide blocking agents, amine blocking agents, imidazoleblocking agents, urea blocking agents, carbamate blocking agents, imineblocking agents, oxime blocking agents or sulfite blocking agents. Amongthem, phenol blocking agents, lactam blocking agents, alcohol blockingagents and oxime blocking agents are used advantageously.

(H-2) Polyepoxide Compound

(1) Compound containing a specified epoxy group represented by thefollowing structural formula ##STR11##

(2) Compound containing a specified epoxy group represented by thefollowing structural formula (XI) ##STR12## wherein R₅₁ represents ahydrogen atom or a methyl group.

The polyepoxide compounds (1) or (2) above are described in detail inEP-A-356970, which is incorporated herein by reference, and detaileddescription thereon is omitted here.

(3) Phenol type novolak glycidyl ether resin represented by thefollowing general formula (XII) ##STR13##

In the formula (XII) above, R₁ and R₂, which are the same or different,independently represent a hydrogen atom, an alkyl group having 1 to 8carbon atoms, an aryl group, an aralkyl group or a halogen atom; R₄ andR₆, which are the same or different, independently represent a hydrogenatom, an alkyl group having 1 to 4 carbon atoms; R₅ represents ahydrogen atom, an alkyl group having 1 to 10 carbon atoms, an arylgroup, an aralkyl group, an allyl group or a halogen atom; R₇ representsan alkyl group having 1 to 10 carbon atoms, an aryl group, an aralkylgroup, an allyl group or a halogen atoms; and n is 0 or an integer of 1to 38. In the general formula (XII) above, a part or all of the benzenerings may be substituted by a naphthalene ring. In the case in which R₇is a hydrogen atom, the bath stability of cationic electrodepositioncoating composition decreases.

The phenol type novolak glycidyl ether resin represented by the formula(XII) above can be produced in the same manner as the component (A)except that among the components (A-1), (A-2) and (A-3) used for theproduction of the phenol-novolak type epoxy resin (component (A))represented by the formula (I) above, R₃ in the general formula (III) asthe component (A-1) is replaced by R₇ (an alkyl group having to 10carbon atoms, an aryl group, an allyl group or a halogen atom).

(4) Compound having two or more glycidyl groups on a glycidylamino groupgroup bonded directly to a carbon atom in the aromatic ring andrepresented by the following general formula (XIII) ##STR14##

In the formula (XIII) above, R₆₁ represents a hydrogen atom or aglycidyl group.

The component (4) above contains an aromatic ring and a glycidyl groupin one molecule, and the glycidyl group is introduced by theglycidylamino group represented by the formula (XIII) above, with thenitrogen atom (N) in the formula (XIII) above being bonded directly toone of the carbon atoms in the aromatic ring.

Generally, the component (4) can be obtained by reacting an anilinederivative with epihalohydrin (preferably epichlorohydrin) in thepresence of an aqueous solution of an alkali metal hydroxide or the like(catalyst). The aniline derivative is a compound containing a benzenering or a naphthalene ring to on of whose carbon atoms is directlybonded an amino group (--NH2). There can be cited, for example,monoaniline derivatives having one amino group (--NH2) directly bondedto one of carbon atoms of a benzene ring or a naphthalane ring such asaniline, o-toluidine, m-toluidine, p-toluidine, o-ethylaniline,m-ethylaniline, p-ethylaniline, p-cresidine, 2,4-xylidine, 3,4-xylidine,o-anisidine, p-anisidine and naphthylamine; dianiline derivatives havingtwo amino groups (--NH2) directly bonded to carbon atoms of a benzenering or a naphthalene ring such as phenylenediamine,2,4-toluylenediamine, diaminobenzanilide, dianisidine, diaminodiphenylether, 3,5-diaminochlorobenzene, 3,3'-dimethylbenzidine, and1,5-naphthylenediamine; and so on.

Also, as the aniline derivative, there may be used a polycondensatecontaining a plurality of aromatic rings bonded to each other through amethylene bond or the like, obtained by reacting the monoanilinederivative or dianiline derivative with aldehydes (e.g., formaldehyde,acetaldehyde, etc.) or ketones (e.g., acetone, methyl ethyl ketone,methyl isobutyl ketone, etc.) using as a catalyst an inorganic acid suchas hydrochloric acid, phosphoric acid or sulfuric acid; an organic acidsuch as p-toluenesulfonic acid or oxalic acid; or a metal salt such aszinc acetate. It is preferred that the polycondensate contains aromaticring repeating units in a number within the range of 2 to 40,particularly 2 to 20. Specific examples of the polycondensate includediaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane,3,3'-diethyl-4,4'-diaminodiphenylmethane, etc. However, this inventionis not limited thereto.

The component (4) may be modified by reacting a portion of glycidylgroups thereon with at least one substance selected from phenols such asbisphenol A, bisphenol F, phenylphenol, nonylphenol, and phenol; higherfatty acids such as dimeric acid, stearic acid; oleic acid, and soy beanoil fatty acid; organic acids such as acetic acid, formic acid, andhydroxyacetic acid; alcohols such as alkyl alcohols, cellosolve, andcarbitol; and so on. Among these, phenols and higher fatty acids areparticularly preferred. Upon the modification, it is preferred to use acatalyst such as zinc borofluoride or tetramethylammonium chloride.

The component (4) which can be used in this invention preferably has anumber average molecular weight within the range of generally about 200to 8,000, particularly 500 to 5,000, and more particularly 500 to 3,000,as measured by vapor pressure infiltration method, and an epoxyequivalent within the range of generally 100 to 2,000, particularly 100to 1,000, and more particularly 100 to 600. As such a component (4),there can be used various commercially available product, for example,GAN (trade name for N,N-diglycidylaniline produced by NIPPON KAYAKU CO.,LTD.), GOT (trade name for N,N-diglycidyl-o-toluidine produced by NIPPONKAYAKU CO., LTD.), MY720 (trade name forN,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane produced byCiba-Geigy (Japan) Limited), MY722 (trade name forN,N,N',N'-tetraglycidyl-3,3'-dimethyl-4,4'-diaminodiphenylmethaneproduced by Ciba-Geigy (Japan) Limited), etc.

(H-3) Compound having two or more carboncarbon unsaturated groups(preferably α,β-unsaturated groups) in a molecule.

The captioned compound includes (1) and (2) below.

(1) Resin having in average at least two, preferably 2.5 to 10, and morepreferably 3 to 7, of 3-alkoxyalkyl-3-(meth)acryloylureido grouprepresented by the following general formula (XIV) per molecule and anumber average molecular weight of 800 to 50,000, preferably 1,000 to10,000, and more preferably 1,000 to 5,000. ##STR15## wherein R₆₃represents a hydrogen atom or a methyl group;

R₆₄ represents an alkylene group having 1 to 4 carbon atoms; and

R₆₅ represents an alkyl group having 1 to 10 carbon atoms.

Details of the resin (1) above are described in U.S. Pat. No. 5,034,109,which is incorporated herein by reference.

(2) A compound having at least two, preferably 2.5 to 10, ofα,β-ethylenically unsaturated groups in a molecule and having no freeisocyanate group, obtained by reacting a polyisocyanate compound with anα,β-ethylenically unsaturated monomer having a hydrogen atom reactivewith the isocyanate group and a functional group represented by thefollowing general formula (XV); and a compound having at least two,preferably 2.5 to 20, of α,β-ethylenically unsaturated groups in amolecule, obtained by reacting a polyisocyanate compound with anα,β-ethylenically unsaturated monomer having a hydrogen atom reactivewith the isocyanate group and a functional group represented by thefollowing general formula (XV) to form a compound having a freeisocyanate group, and then reacting this compound with a resin having aprimary, secondary amino group and/or a hydroxyl group. ##STR16##

Specific explanation of the compounds (2) above is found in U.S. Pat.No. 4,320,220, which is incorporated herein by reference.

Mixing ratios of the cationic resin (U) and the hardening agent (H) inthe cationic electrodeposition coating composition (V) are not criticaland may be selected freely depending on the purposes. For example, it ispreferred that the component (U) is within the range of generally 30 to90%, particularly 40 to 85%, and more particularly 50 to 80%, and thecomponent (H) is within the range of generally 70 to 10%, particularly60 to 15%, and more particularly 50 to 20%, based on total weight of thecomponents.

In order to facilitate dispersion or dissolution of the cationic rein(U) in water upon production of the coating composition (V), it ispreferred to have a portion or all of the basic groups in the resin (U)neutralized with an acid component such as formic acid, acetic acid,lactic acid, butyric acid or propionic acid.

Resin for Self-Hardening Coating Composition (W)

This resin (W) can be obtained by partially reacting the cationic resin(U) with the hardening agent (H). The cationic electrodeposition coatingcomposition (X) containing as a main component the self-hardening resin(W) can give rise to a crosslinked and hardened coating film when heatedas it is without being blended with a hardening agent.

While the kind of the hardening agent (H) used here is not limitedparticularly, partially blocked polyisocyanate compounds that is readilysusceptible to partial reaction are preferred. The resin forself-hardening coating composition (W) can be prepared by reacting thecationic resin (U) with a partially blocked polyisocyanate compoundhaving a free isocyanate group obtained by blocking a polyisocyanatecompound having two or more isocyanate groups with a blocking agentuntil all or substantially all of the free isocyanate groups come to benot left unreacted, in an inert organic solvent at 40° to 200° C. tosuch an extent that (no substantially no) free isocyanate group remains.The proportion to the partially blocked polyisocyanate compound to thecationic resin (U) may be selected freely taking its hardenability intoconsideration and depending on the purpose. For example, it is preferredthat the proportion in mole of the partially blocked polyisocyanatecompound to total of the primary or secondary amino group and hydroxylgroup contained in the cationic resin (U) is 0.4 to 1.50, particularly0.7 to 1.3.

The resin of self-hardening coating composition (W) may be the one inwhich α,β-unsaturated double bond is introduced in the aforementionedcationic resin (U). The resin (W) of this type can be obtained byreacting a monoisocyanate compound having an α,β-unsaturated double bondand an isocyanate group in one molecule contained in the cationic resin(U) with a primary or secondary amino group and/or a hydroxyl group, themonoisocyanate compound being obtained by reacting all but oneisocyanate groups in a polyisocyanate compound having at least twoisocyanate groups with a compound having α,β-unsaturated double bond anda functional group containing active hydrogen such as a hydroxyl groupor a secondary amido group (for example, hydroxyalkyl (meth)acrylate,methylol (meth)acrylamide, alkoxyalkyl (meth)acrylamide, etc.). In thiscase, it is preferred that the amount of α,β-unsaturated double bond tobe introduced is within the range of generally 200 to 2,000 unsaturationequivalents, particularly 300 to 1,500 unsaturation equivalents, in thesolids content of the resin.

Cationic Electrodeposition Coating Composition (X)

The cationic electrodeposition coating composition (X) contains as amain component a protonated product obtained by protonating the resinfor self-hardening coating composition (W) with the aforementionedacidic compound, and can be obtained by dissolving or dispersing theresin in water. While it is not mandatory to blend the hardening agent(H) therewith, it may be blended as necessary.

The cationic electrodeposition coating composition (V) and (X) of thisinvention, which contain as a main component either the cationic resin(U) or the resin self-hardening coating composition (W), may further beblended with one or more of an extender pigment, a corrosion-resistantpigment, a dispersant, a cising-preventing agent, a hardeningaccelerator, etc., as necessary. Among these additives, the pigments areblended preferably in the form of a pigment dispersed paste (Y) asdescribed below.

Pigment-Dispersed Paste (Y)

The pigment-dispersed paste (Y) can be obtained by dispersing a mixtureof at least one member selected from the cationic resin (U) and theresin for self-hardening coating composition (W), and a pigment(coloring pigment, extender pigment, corrosion-resistant pigment, etc.)in water. Further, this may contain one or more of a plasticizer, awetting agent, a surfactant, a defoaming agent, etc., as necessary.

Mixed dispersion of each component can be performed using a ball mill, asand mill, a Crowles dissolver, a continuous disperser or the like. Itis preferred to divide the pigment to a desired particle size and wetthe particles with the aforementioned resin. The particle size of thepigment after dispersion is preferably below 10 μm (about 6 to 8 afterHerman grind gauge). It is preferred to perform this dispersion inwater. In this case, it is desirable to have a portion or all of thebasic groups in the cationic resin (U) and the resin for self-hardeningcoating composition (W) protonated with the aforementioned acidiccompound to for an aqueous dispersion. It is preferred to use the acidiccompound in such as amount that the neutralization value of the resin iswithin the range of generally 5 to 200, particularly 10 to 150, and moreparticularly 20 to 100, as calculated in terms of KOH (mg/g). While thewater content of the aqueous dispersion as the pigment-dispersed paste(Y) is not limited particularly, it is preferably within the range ofusually about 20 to 80% by weight, particularly 30 to 70% by weight.

The kind of the pigment used in the pigmentdispersed paste (Y) is notlimited particularly. The pigment can be, for example, coloring pigmentssuch as carbon black, titanium white, lead white, lead oxide, and redoxide; extender pigments such as antimony oxide, zinc oxide, basic leadcarbonate, basic lead sulfate, barium carbonate, calcium carbonate,aluminum silica, magnesium carbonate, magnesium silica, clay, and talc;corrosionresistant pigments such as strontium chromate, lead chromate,basic lead chromate, red lead oxide, lead silicate, basic lead silicate,lead phosphate, basic led phosphate, lead tripolyphosphate, leadsilicochromated yellow lead oxide, lead cyanamide, calcium plumbate,lead suboxide, and lead sulfate. It is preferred that the proportion ofthe pigment to the resin contained in the pigment paste (Y) for coatingcomposition is within the range of usually 2/1 to 7/1, particularly 3/1to 6/1, by weight of the solids content.

The cationic electrodeposition coating composition prepared as describedabove can be cationically electrodeposition coated on a suitableelectroconductive substrate (article to be coated), and the resultingfilm can be heated at a temperature of, for example, 80° to 250° C.,preferably 120° to 160° C., for hardening.

In particular, in order to fully harden an electrodeposition coatingfilm of the cationic electrodeposition coating composition of thisinvention at a low temperature of 160° C. or lower, it is effective toadd as a catalyst one or more of metal compounds selected from leadcompounds, zirconium compounds, cobalt compounds, aluminum compounds,manganese compounds, copper compounds, zinc compounds, iron compounds,chromium compounds, nickel compounds, tin compounds, etc. Specificexample of these metal compounds include chelate compounds such aszirconium acetylacetonate, cobalt acetylacetonate, aluminumacetylacetonate, and manganese acetylacetonate; chelating reactionproducts between a compound having a β-hydroxylamino structure and lead(II) oxide; carboxylates such as lead 2-ethylhexanoate, leadnaphthenate, lead octanoate, lead benzoate, lead acetate, lead lactate,lead formate, lead glycolate, and zirconium octanoate; and so on.

The aforementioned metal compound may be used in such an amount that theratio of the metal content to the solids content of the cationic resin(U) or the resin for self-hardening coating composition (W) to thesolids is generally 10% by weight or less, preferably 0.5 to 5% byweight.

The cationic electrodeposition coating composition obtained according tothis invention is excellent in water dispersibility at a low degree ofneutralization when the cationic group which endows the cationic resin(U) or the resin for self-hardening coating composition (W) with waterdispersibility is a tertiary amino group, and hence the composition ofthis invention exhibits high pH and high throwing power. Since a largeamount of the compound having a primary hydroxyl group can be reactedwith the cationic resin (U), a large number of primary hydroxyl groups,which are functional groups useful in various hardening types, can beintroduced in the resin, resulting in improvement in hardenability, thusproviding the resin composition suitable for cathode electrodepositioncoating.

The method for forming an electrodeposition coating film on anelectroconductive substrate with the cationic electrodeposition coatingcomposition of this invention is not limited particularly, and themethod may be performed under ordinary conditions for cationicelectrodeposition coating. For example, a hardening catalyst or the likeadditive may be blended with the electrodeposition coating compositionas necessary to prepare a cationic electrodeposition bath havingconcentration (solids content concentration) within the range of 5 to40% by weight, preferably 10 to 25% by weight, and a bath pH within therange of 5 to 8, preferably 5.5 to 7. On this occasion, it is preferredto use the article to be coated as a cathode, and a stainless or carbonplate as an anode. While electrodeposition coating conditions are notlimited particularly, generally it is desirable to performelectrodeposition under the conditions of a bath temperature: 20° to 30°C., voltage: 100 to 400 V, preferably 200 to 300 V, current density:0.01 to 3 A/dm.sup. 2, current application time: 1 to 5 minutes,electrode area ratio (A/C) 2/1 to 1/2, electrode distance: 10 to 100 cm,and with stirring.

Further, the cationic electrodeposition coating composition of thisinvention is excellent in water dispersibility, storage stability, bathstability, corrosion resistance, smoothness, etc., since it uses thecationic resin (U) and the resin for self-hardening coating composition(W).

The cationic electrodeposition coating composition provided by thisinvention has excellent water dispersibility at a low degree ofneutralization when the cationic group which endows the cationic resin(U) or the resin for self-hardening coating composition (W) with waterdispersibility is a tertiary amino group, and therefore the compositionof this invention exhibits high pH and high throwing power. Since alarge amount of the compound having a primary hydroxyl group can bereacted with the cationic resin (U), a large number of primary hydroxylgroups, which are functional group useful in various hardening types,can be introduced in the resin, resulting in improvement inhardenability, thus providing a resin composition suitable for cathodeelectrodeposition coating.

EXAMPLES

Hereinafter, this invention will be described in more detail byexamples. Unless otherwise indicated specifically, all "%" and "part" or"parts" used herein are by weight.

I. Preparation Example (1) Preparation of Amine Compound (B)

(B-1)

A reaction vessel equipped with a thermometer, a stirrer, a refluxcondenser, and a water separator was charged with 285 parts of stearicacid, 104 parts of hydroxyethylaminoethylamine, and 80 parts of toluene,which were mixed and stirred with slowly heating to increase thetemperature to separate and remove 18 parts of reaction water whileremoving toluene as necessary. Thereafter, remaining toluene wasevaporated off under reduced pressure to obtain an amine compound (B-1)having an amine value of 150 and a solidification point of 76° C.

(B-2): (For Comparison)

A flask equipped with a stirrer, a thermometer, a dropping funnel, and areflux condenser was charged with 39 parts of monoethanolamine, whichwas kept at 60° C., and 100 parts of N,N-dimethylaminopropylacrylamidewas added thereto dropwise, followed by reaction at 60° C. for 5 hoursto obtain an amine compound (B-2).

(2) Preparation of Phenolic Compound (C)

(C-1)

A flask equipped with a stirrer, a thermometer, a dropping funnel, and areflux condenser was charged with 105 parts of diethanolamine, 760 partsof diglycidyl ether of bisphenol A having an epoxy equivalent of 190,456 parts of bisphenol A, and 330 parts of ethylene glycol monobutylether, and the mixture was allowed to react at 150° C. until the amountof the remaining epoxy group became 0 to obtain a phenolic compound(C-1) having a solids content ratio of 80%.

(C-2)

A flask equipped with a stirrer, a thermometer, a dropping funnel, and areflux condenser was charged with 170 parts of phenylphenol, 760 partsof diglycidyl ether of bisphenol A having an epoxy equivalent of 190,456 parts of bisphenol A, 0.2 part of tetramethylammonium chloride, and346 parts of ethylene glycol monobutyl ether, and the mixture wasallowed to react at 150° C. until the amount of the remaining epoxygroup became 0 to obtain a phenolic compound (C-2) having a solidscontent ratio of 80%.

(C-3)

A flask equipped with a stirrer, a thermometer, a dropping funnel, and areflux condenser was charged with 280 parts of oleic acid, 760 parts ofdiglycidyl ether of bisphenol A having an epoxy equivalent of 190, 456parts of bisphenol A, 0.2 part of tetramethylammonium chloride, and 374parts of ethylene glycol monobutyl ether, and allowed to react at 150°C. until the amount of the remaining epoxy group became 0 to obtain aphenolic compound (C-3) having a solids content ratio of 80%.

(C-4)

A flask equipped with a stirrer, a thermometer, a dropping funnel, and areflux condenser was charged with 370 parts of amine compound (B-1)above, 760 parts of diglycidyl ether of bisphenol A having an epoxyequivalent of 190, 456 parts of bisphenol A, and 397 parts of ethyleneglycol monobutyl ether, and allowed to react at 150° C. until the amountof the remaining epoxy group became 0 to obtain a phenolic compound(C-4) having a solids content ratio of 80%. The value of q in thegeneral formula (IX) above was about 3.

(3) Preparation of Hardening Agent (H)

(H-1)

The 174 parts of tolylene diisocyanate was added dropwise 268.5 parts ofethylene glycol monoethyl ether at 50° C. over 2 hours, and the mixturewas kept at 80° C. over 3 hours to obtain a hardening agent (H-1) havinga solids content ratio of 80%.

(H-2)

A reaction vessel equipped with a thermometer, a stirrer, a refluxcondenser, a dropping funnel was charged with 222 parts of isophoronediisocyanate, 83.4 parts of methyl isobutyl ketone, 0.1 part of dibutylin dilaurate, and 1 part of hydroquinone monomethyl ether, to which wasadded dropwise 116 parts of hydroxyethyl acetate at 100° C., and themixture was allowed to react until NCO value of 112 was reached toobtain a hardening agent (H-2).

(H-3)

A flask equipped with a stirrer, a thermometer, and a reflux condenserwas charged with 1917 parts of EPICRON N-695 (DAINIPPON INK ANDCHEMICALS INCORPORATED, epoxy equivalent: 213, n=7), 590 parts ofethylene glycol monobutyl ether, 440 parts of nonylphenol, and 0.2 partof tetramethylammonium chloride, and the mixture was allowed to react150° C. until epoxy equivalent of 350 was reached to obtain a hardeningagent (H-3).

(H-4)

A flask equipped with a stirrer, a thermometer, and a reflux condenserwas charged with 1917 parts of EPICRON N-695 (DAINIPPON INK ANDCHEMICALS INCORPORATED, epoxy equivalent: 213, n=7), 620 parts ofethylene glycol monobutyl ether, 560 parts of tall oil fatty acid, and0.2 part of tetramethylammonium chloride, and the mixture was allowed toreact 150° C. until epoxy equivalent of 370 was reached to obtain ahardening agent (H-4).

(H-5)

A mixture of 100 parts of EHPE-3150 (epoxy equivalent: 180, produced byDAICEL CHEMICAL INDUSTRIES, LTD.), and 25 parts of ethylene glycolmonobutyl ether was heated at 100° C. for dissolution to obtained a ahardening agent (H-5) having solids content ratio of and an epoxyequivalent of 180.

(H-6)

A flask equipped with a stirrer, a thermometer, and a reflux condenserwas charged with 100 parts of ESMB-260 (SUMITOMO CHEMICAL CO., LTD.,epoxy equivalent: 260), and 25 parts of ethylene glycol monobutyl ether,and the mixture was heated for dissolution to obtain a hardening agent(H-6).

(H-7)

A flask equipped with a stirrer, a thermometer, and a reflux condenserwas charged with 100 parts of MY720 (CIBA GEIGY (JAPAN) LIMITED,N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane), and 25 parts ofethylene glycol monobutyl ether, and the mixture was heated fordissolution to obtain a hardening agent (H-7) having a nonvolatilecontent of 80% and an epoxy equivalent of 115.

(H-8)

A flask equipped with a stirrer, a thermometer, a dropping funnel, and areflux condenser was charged with 666 parts of isophorone diisocyanate,11.4 parts of p-benzoquinone, and 11.4 parts of dibutyltin dilaurate.After the temperature was elevated to 120° C., 471 parts ofN-n-butoxymethylacrylamide was added dropwise thereto while keeping thattemperature, and the reaction was continued until NCO value of 110 wasreached when 134 parts of trimethylolpropane was added. The mixture wasallowed to react 120° C. until NCO value became 0 when 295 parts ofethylene glycol monobutyl ether was added to obtain a hardening agent(H-8).

II. Examples Example 1

Cationic Resin (U-1)

A flask equipped with a stirrer, a thermometer, a dropping funnel, and areflux condenser was charged with 1008 parts of DEN-438 (epoxyequivalent: 180, produced by DOW CHEMICAL JAPAN CO., LTD., component A),506 parts of ethylene glycol monobutyl ether. After dissolution, 373parts of diethanolamine (component B), 1651 parts of phenolic compound(C-1), and 742 parts of an amino compound (B-1) were further charged,and slowly heated while mixing with stirring. The mixture was allowed toreact 150° C. Confirming that the amount of the remaining epoxy groupreached 0, a cationic resin (U-1) was obtained. This had a solid contentratio of 80%, an amine value of 94, a primary hydroxyl group equivalentof 363, and component (A) content ratio of 30.1%.

Examples 2 to 6

Resin Composition Containing Cationic Resin (U-2)

A flask equipped with a stirrer, a dropping funnel, and a refluxcondenser was charged components (A), (B) and (C), and a solvent asshown in Table 1, and the mixture was allowed to react 150° C. slowlywhile mixing with stirring. Confirming that the amount of the remainingepoxy group reached 0, the reaction was terminated to obtained acationic resin (U).

Then, in the presence of the cationic resin (U), other components shownin Table 1 were mixed and allowed to react 150° C. for 5 hours.Confirming that the amount of the remaining epoxy group reached 0, thereaction was terminated to obtained a composition containing thecationic resin (U).

                                      TABLE 1                                     __________________________________________________________________________                        Example                                                                       2    3    4    5    6                                     __________________________________________________________________________    Cationic Resin (U)  U-2  U-3  U-4  U-5  U-6                                   Component (A)                                                                         BREN-S      1710                                                              DEN-438          1080      1080 1080                                          EOCN-102S             1290                                            Component (B)                                                                         (B-1)       742  742  371  371                                                Diethanolamine                                                                            315  210  420  378  483                                           N-Methylethanolamine                                                                           45                                                   Component (C)                                                                         (C-1)       1651                1651                                          (C-2)            1733                                                         (C-3)                 1870                                                    (C-4)                      1984                                       Solvent Ethylene glycol                                                                           692  501  520  439  373                                           monobutyl ether                                                       Other component                                                               Ethylene glycol monobutyl ether                                                                   1433 1433 1433 1433 1623                                  Bisphenol A diglycidyl ether                                                                      3610 3610 3610 3610 2850                                  Bisphenol A         1596 1596 1596 1596 1596                                  Diethanolamine      525  525  525  525  525                                   Polypropylene glycol diglycidyl ether   1520                                  Solids content ratio (%)                                                                          80   80   80   80   80                                    Amine value         57   55   60   66   64                                    Primary hydroxyl group equivalent                                                                 491  550  490  473  439                                   Component (A) content ratio (%)                                                                   17.4 11.1 13.9 11.1 10.8                                  __________________________________________________________________________     Note:                                                                         BERNS: Brominemodified novolakphenol polyglycidyl ether having an epoxy       equivalent 285 (NIPPON KAYAKU CO., LTD.)                                      DEN438: Novolakphenol polyglycidyl ether having an epoxy equivalent 180       (DOW CHEMICAL JAPAN CO., LTD.)                                                ECON102S: Cresolnovolak phenol polyglycidyl ether having an epoxy             equivalent of 215 (NIPPON KAYAKU CO., LTD.)                                   Polypropylene glycol diglycidyl ether: Epoxy equivalent; 380             

Example 7

A flask equipped with a stirrer, a thermometer, a dropping funnel, and areflux condenser was charged with 1,008 parts of DEN-438 (epoxyequivalent: 180, produced by DOW CHEMICAL JAPAN CO., LTD.), and 1,045parts of ethylene glycol monobutyl ether. After heating for dissolution,378 parts of diethanolamine, 742 parts of the amino compound (B-1), and2,052 parts of bisphenol A were further charged, and slowly heated whilemixing with stirring. The mixture was allowed to react 150° C., and itwas confirmed that the amount of the remaining epoxy group reached 0.

Thereafter, 630 parts of diethanolamine, 4,370 parts of diglycidyl etherof bisphenol A having an epoxy equivalent 190, and 1,250 parts ofethylene glycol monobutyl ether were added, and the mixture was allowedto react 150° C. for 5 hours. It was confirmed that the amount of theremaining epoxy group reached 0 to obtain a cationic resin (U-7) havinga solids content of 80%, an amine value of 61, a primary hydroxyl groupequivalent of 510, and a component (A) content ratio of 11%.

Example 8

Resin for Self-Hardening Coating Composition (W-1)

A flask equipped with a stirrer, a thermometer, a dropping funnel, and areflux condenser was charged with 1,008 parts of DEN-438 (epoxyequivalent: 180, produced by DOW CHEMICAL JAPAN CO., LTD.), and 931parts of methyl isobutyl ketone. After heating for dissolution, 378parts of diethanolamine, 742 parts of the amino compound (B-1), and1,596 parts of bisphenol A were further charged, and slowly heated whilemixing with stirring. The mixture was allowed to react 150° C., and itwas confirmed that the amount of the remaining epoxy group reached 0.

Thereafter, 630 parts of diethanolamine, 3,610 parts of diglycidyl etherof bisphenol A having am epoxy equivalent 190, and 1,060 parts of methylisobutyl ketone were added, and the mixture was allowed to react 150° C.until the amount of the remaining epoxy group reached 0, followed bycooling down to 80° C.

Next, 3,803 parts of the hardening agent (H-2) was added, the mixturewas allowed to react at 80° C. until the NCO value reached 0. Then,2,752 parts of ethylene glycol monobutyl ether was added, followed byheating in order to evaporate off 2,752 parts of methyl isobutyl ketoneunder reduced pressure to obtain a resin for self-hardening coatingcomposition (W-1) having a solids content of 80%, an amine value of 51,a primary hydroxyl group equivalent of 1,223, a component (A) content of9%, an α,β-unsaturated double bond equivalent of 1,223.

Comparative Example 1

A flask equipped with a stirrer, a thermometer, a dropping funnel, and areflux condenser was charged with 21 parts of diethanolamine, 950 partsof diglycidyl ether of bisphenol A having an epoxy equivalent 190, and340 parts of polypropylene glycol diglycidyl ether having an epoxyequivalent 340, and 456 parts of bisphenol A, and the mixture was slowlyheated while mixing with stirring. The mixture was gently heated withstirring to be reacted at 120° C. and, after confirming that the amountof the remaining epoxy equivalent reached 980, 492 parts of ethyleneglycol monobutyl ether was added, and 158 parts of diethanolamine and 43parts of the amino compound (B-2) were added with keeping thetemperature at 100° C. The mixture was allowed to react until increasein viscosity stopped to obtain a comparative resin ((1)) having a solidscontent of 80%, an amine value of hand a primary hydroxyl groupequivalent of 532, which contained no component (A).

Comparative Example 2

A flask equipped with a stirrer, a thermometer, a dropping funnel, and areflux condenser was charged with 1,008 parts DEN-438 (epoxy equivalent:180, produced by DOW CHEMICAL JAPAN CO., LTD., component A), and 399parts of ethylene glycol monobutyl ether. After dissolution, 588 partsof diethanolamine was further charged, and slowly heated while mixingwith stirring. The mixture was allowed to react 150° C. until it wasconfirmed that the amount of the remaining epoxy group reached 0.

Thereafter, 630 parts of diethanolamine, 1,520 parts of polypropyleneglycol diglycidyl ether having an epoxy equivalent 380, 3,040 parts ofdiglycidyl ether of biphenol A having an epoxy equivalent of 190, 1,596parts of bisphenol A, and 1,696.5 parts of ethylene glycol monobutylether were added, and the mixture was allowed to react 150° C. for 5hours when it was confirmed that the amount of the remaining epoxy groupreached 0 to obtain a cationic resin ((2)) having a solids content of80%, an amine value of 78, a primary hydroxyl group equivalent of 361,and a component (A) content of 12%. (No component (c) was used.)

Example 9

Pigment-Dispersed Paste (Y-1)

After kneading a mixture of 10 parts o the cationic resin (U-1), 20parts of titanium white (TAIPEK CR93, produced by ISHIHARA SANGYO KAISHALTD.), 2 parts of carbon (MA-7, produced by MITSUBISHI CHEMICALINDUSTRIES LIMITED) 4 parts of aluminum tripolyphosphate (K WHITE 84,produced by TIEKOKU KAKOU CO., LTD.), 24 parts of clay (GEIKIELITE,GEIKIELITE CHEMICAL CO., LTD.), 0.4 part of acetic acid, and 39.6 partsof deionzied water, the mixture was dispersed with 200 parts of glassbead in a paint shaker to obtain a pigment-dispersed paste (Y-1) havinga grit of 10 μm or less by a particle gauge, and having a solids contentof 58%.

Examples 10 to 18 and Comparative Examples 1 and 2

A hardening agent and neutralizing agent were added to the cationicresin described above in the formulation shown in Table 2 below.Deionized water was added to the mixture while stirring well to obtain aemulsion having a solids content of 30%.

A catalyst shown in Table 2 and the pigmentdispersed paste (Y-1) weremixed in advance, and the resulting mixture was mixed with 333 pars ofthe aforementioned emulsion. Adding deionized water thereto to obtain anelectrodeposition coating composition having a solid content of 20%.

                                      TABLE 2                                     __________________________________________________________________________    Cationic    Hardening                                                                           Neutralizing                                                                           Deionized                                                                           Catalyst                                     resin       Agent Agent    Water Kind   Amount                                __________________________________________________________________________    Example                                                                       10   U-1                                                                              62.5                                                                              H-4                                                                              62.5                                                                             Formic acid                                                                          1.2                                                                             207.1 Lead octenate                                                                        2.6                                   11   U-2                                                                              93.7                                                                              H-3                                                                              31.3                                                                             Acetic acid                                                                          1.6                                                                             204.1 Lead octenate                                                                        2.6                                   12   U-3                                                                              75.0                                                                              H-3                                                                              50.0                                                                             Acetic acid                                                                          1.6                                                                             204.1 Lead octenate                                                                        2.6                                   13   U-4                                                                              69.0                                                                              H-8                                                                              56.0                                                                             Formic acid                                                                          1.2                                                                             207.1 Lead octenate                                                                        2.6                                   14   U-5                                                                              93.7                                                                              H-5                                                                              31.3                                                                             Acetic acid                                                                          1.6                                                                             204.1 Lead octenate                                                                        2.6                                   15   U-6                                                                              81.0                                                                              H-6                                                                              44.0                                                                             Formic acid                                                                          1.2                                                                             207.1 Zinc octenate                                                                        2.6                                   16   U-6                                                                              100 H-7                                                                              25.0                                                                             Formic acid                                                                          1.2                                                                             207.1 Zinc octenate                                                                        2.6                                   17   U-7                                                                              75.0                                                                              H-4                                                                              50.0                                                                             Acetic acid                                                                          1.6                                                                             204.1 Zinc octenate                                                                        2.6                                   18   W-1                                                                              125 --    Formic acid                                                                          1.2                                                                             207.1 Zinc octenate                                                                        2.6                                   C. Ex.                                                                         1   (1)                                                                              93.7                                                                              H-5                                                                              31.3                                                                             Formic acid                                                                          1.2                                                                             207.1 Zinc octenate                                                                        2.6                                    2   (2)                                                                              93.7                                                                              H-5                                                                              31.3                                                                             Formic acid                                                                          1.2                                                                             207.1 Zinc octenate                                                                        2.6                                   __________________________________________________________________________     C. Ex.: Comparative Example                                              

Using the electrodeposition coating baths obtained in Examples 10 to 18and Comparative Examples 1 and 2, zinc phosphate-treated steel platesand nonprocessed steel plates were electrodeposited at a bathtemperature of 25° C. and at a voltage of 100 to 250 V for 3 minutes,and then baked at 150° C. for 30 minutes to obtain coated plates. Amongthe plates, those having a hardened coating film thickness of 20 μm wereselected, and subjected to coating film performance tests. Resultsobtained are shown in Table 3.

                  TABLE 3                                                         ______________________________________                                        Particle Size           Smoothness                                                       After            of Coated                                                                             SST                                       Initial    Storage   PH     surface Processed                                 ______________________________________                                        Example                                                                       10     0.10    0.10      6.2  0       Acceptable                              11     0.18    0.20      6.4  0       Acceptable                              12     0.25    0.23      6.4  0       Acceptable                              13     0.20    0.20      6.0  0       Acceptable                              14     0.18    0.20      6.3  0       Acceptable                              15     0.20    0.18      6.0  0       Acceptable                              16     0.18    0.20      6.0  0       Acceptable                              17     0.15    0.16      6.5  0       Acceptable                              18     0.10    0.10      6.0  0       Acceptable                              C. Ex.                                                                         1     0.25    0.6>      6.1  Δ Unacceptable                             2     0.6>    precipitated                                                                            6.0  0       Unacceptable                            ______________________________________                                         C. Ex.: Comparative Example                                              

Test Methods

Stability

An emulsion having a solids content of 30% was stored at 30° C. for 15days, and change in particle diameter of the emulsion after the storagewas measured using NANOSIZER N-4, produced by COULTER ELECTRON INS. Witha particle size of below 0.3 μm, water dispersibility is judged to beexcellent.

pH: Measurement was made by the method described in JIS Z-8802-78 usingthe automatic pH meter described in JIS K-0802-83.

Smoothness of coated surface

The coated surface coated and baked for hardening under the conditionsdescribed above were evaluated by visual observation.

SST Salt spray resistance

Test coating compositions were coated on the plates at a voltage enoughto obtain a coating film thickness of 20 μm under the coating conditionsdescribed above, and the coated plates were baked at 160° C. for 20minutes. The plates thus treated were tested according to the techniquedescribed in JIS Z-2871. When welling of the coating film in a region ofa creek formed at a distance of 2.0 mm from a cut on the coating film onboth sides thereof and in other regions was at most 8F according to thegrating of ASTM, of plates were judged to be acceptable. Test period was1,000 hours.

We claim:
 1. A resin composition for an aqueous coating composition,comprising as a main component a cationizable resin (U) having a primaryhydroxyl group obtained by reacting:(A) a phenol-novolak type epoxyresin represented by the following general formula (I) ##STR17## whereinR₁ and R₂, which are the same or different, independently represent ahydrogen atom, an alkyl group having 1 to 8 carbon atoms, an aryl group,an aralkyl group or a halogen atom; R₃ represents a hydrogen atom, analkyl group having 1 to 10 carbon atoms, an aryl group, an aralkylgroup, an allyl group or a halogen atom;R₄ and R₆, which are the same ordifferent, independently represent a hydrogen atom, an alkyl grouphaving 1 to 4 carbon atoms or a glycidyloxyphenyl group; R₅ represents ahydrogen atom, an alkyl group having 1 to 10 carbon atoms, an arylgroup, an aralkyl group, an allyl group or a halogen atom; and n is aninteger of 1 to 38, (B) a secondary amine compound having primaryhydroxyl group(s) selected from the group consisting ofN-alkylalkanolamines, dialkanolamines, addition products of amonoalkanolamine with an α,β-unsaturated carbonyl compound, and aminecompounds represented by the formula (VII) below ##STR18## wherein m isan integer of 1 to 6;R₂₁ is hydrocarbon chain having 4 to 36 carbonatoms which may contain a hydroxyl group and/or a polymerizableunsaturated group; and (C) a phenol compound having at least onephenolic hydroxyl group per molecule, said phenol compound being presentin an amount within the range of 0.05 to 1.5 moles per mole of saidepoxy resin (A).
 2. The composition as claimed in claim 1, wherein saidepoxy resin (A) has a number average molecular weight within the rangeof about 400 to about 8,000 as measured by a vapor pressure-osmoticpressure method.
 3. The composition as claimed in claim 1, wherein saidepoxy resin (A) has an average 3.5 to 10 glycidyl groups per molecule.4. The composition as claimed in claim 1, wherein said epoxy resin (A)has an epoxy equivalent within the range of 180 to 2,000.
 5. Thecomposition as claimed in claim 1, wherein R₁ and R₂ independentlyrepresent a hydrogen atom, a methyl group, a chlorine atom or a bromineatom; R₃ and R₅ independently represent a methyl group, a tert-butylgroup, a nonyl group, a phenyl group, a chlorine atom, or a bromineatom; R₄ and R₆ independently represent a hydrogen atom; and n aninteger of 3 to
 25. 6. The composition as claimed in claim 1, whereinsaid amine compound (B) is a mixture of an amine compound represented bythe formula (VII) and diethanolamine.
 7. The composition as claimed inclaim 1, wherein said phenol compound (C) contains at least 1,preferably 1 to 4, per molecule of structural units represented byformula (VIII) below: ##STR19## wherein R₃₃ and R₃₄, which are the sameor different, independently represent a hydrogen atom, an alkyl grouphaving 1 to 10 carbon atoms, an aryl group, an aralkyl group, an allylgroup or a halogen atom.
 8. The composition as claimed in claim 1,wherein said phenol compound (C) is selected from the group consistingof bis(4-hydroxyphenyl)-2,2-propane, 4,4'-dihydroxybenzophenone,bis(4-hydroxyphenyl)-1,1-ethane, bis(4-hydroxyphenyl)-1,1-isobutane,bis(4-hydroxy-tert-butylphanyl)-2,2-propane,bis(2-hydroxynaphthyl)methane, 1,5-dihydroxynaphthalene,bis(2,4-dihydroxyphenyl)methane,1,1,2,2,-tetrakis(4-hydroxyphenyl)ethane, 4,4'-dihydroxydiphenyl ether,4,4'-dihydroxydiphenylsulfone, phenolnovolak, and cresol-novolak;monophenol compounds such as phenol, nonylphenol, α- or β-naphthol,p-tert-octylphenol, and o- or p-phenylphenol.
 9. The composition asclaimed in claim 1, wherein said phenol compound (C) has an average 0.3to 3 phenolic hydroxyl group-containing function groups per moleculesaid functional group being represented by formula below ##STR20##wherein R₃₁ and R₃₂, which are the same or different, independentlyrepresent an alkyl group having 1 to 4 carbon atoms; andR₃₃ and R₃₆,which are the same or different, independently represent a hydrogenatom, an alkyl group having 1 to 10 carbon atoms, an aryl group, anaralkyl group, an allyl group or a halogen atom.
 10. The composition asclaimed in claim 9, wherein said phenol compound (C) has a numberaverage molecular weight within the range of 500 to 2,000.
 11. Thecomposition as claimed in claim 9, wherein said phenol compound (C) isbis(4-hydroxyphenyl)-2,2-propane or bis(4-hydroxyphenyl)methane.
 12. Thecomposition as claimed in claim 1, where in said phenol compound is acompound represented by formula (IX) below ##STR21## wherein q is 0 orinteger of 1 to 7; andR₃₈ represents a residual group of an activehydrogen-containing compound.
 13. The composition as claimed in claim 1,wherein said epoxy resin (A) is present in an amount of 0.5 to 75% byweight based on total weight of said components (A), (B) and (C). 14.The composition as claimed in claim 1, wherein said amine compound (B)is present in a proportion such that a hydroxyl group equivalent of saidcationizable resin (U) is within the range of 250 to 2,000.
 15. Thecomposition as claimed in claim 1, wherein said cationizable resin (U)has a number average molecular weight within the range of 1,000 to200,000.
 16. The composition as claimed in claim 1, wherein saidcationizable resin (U) has a hydroxyl group equivalent within the rangeof 250 to 2,000, and an amine value within the range of 15 to 200.